Increasing max temperature on my water heater?


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Old 03-04-15, 06:08 PM
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Increasing max temperature on my water heater?

Hello. I have an electric Bradford White water heater, and 2 daughters. That means I always run out of hot water!
My hot water system has a thermostatically controlled mixing valve set at 116 degrees, which is located immediately on the outlet of the heater, so scalding is not a factor. I want to increase the maximum temperature in the heater to, in effect, increase my hot water storage supply. I have turned the thermostats in the unit all the way up, but it peaks at about 120 degrees. How can I increase my maximum temp? replace the thermostat? Is it possible to adjust further?
 
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Old 03-04-15, 08:37 PM
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Increasing the temperature would do nothing but give you a higher electric bill and possibly start tripping the relief valve.
I've lived in houses with just a 40 gal. tank with 5 people living there and never once ran out of hot water.
How old is this heater?
Checked the elements to make sure there both working?
How big is the tank?
 
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Old 03-04-15, 08:53 PM
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Increasing the temperature would increase the quantity of stored BTU's, which equates to additional gallons of hot water downstream of the tempering valve.

The reason I have the tempering valve is because there is a wood boiler in the system as well, and when it is fired it heats with 160-180 degree water. The water heater temp frequently gets up to 150 - 160 then. And we never run out of hot water. When the boiler is on, I turn the electric breaker to the water heater off. But when the wood boiler is not fired, and I am heating water with electricity it only goes to 120 and I run out a lot.
It's a 40 gallon tank, 10 years old, both elements are working, 4500W each.
 
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Old 03-05-15, 05:25 AM
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Hi jr,
having raised 2 daughters as well I do understand the high hot water use. But a max 120 indicates something is wrong. How are you measuring that temperature? The water heater should easily reach 140 to 160 as 120 is below sanitizing temperature.

You are correct that a higher tank temp should decrease the total volume used, but 116 is on the low side to start with. I had mine at 125 and the wife made a firm request that I increase it, now 140. At 125 I didn't need to mix cold water for a shower, but at the 140 (ouch) I mix.

Now, do you have a low flow shower head? The ones I installed and recommend are not only low flow, but have an additional adjustment so the user can reduce it even further or even shut it off at times during the shower. Getting family members to recognize the cost/problem and pitch in by modifying their shower times and methods is important.

Bud
 
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Old 03-05-15, 05:51 AM
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I have never seen a water heater thermostat that maxed out at 120f so I agree with Bud9051 that something is wrong if that's as hot as your heater will get. I too am curious how you are measuring the temperature as 120f is probably within the margin of error for the mixing valve if you are testing at a spigot.

I would check that both thermostats and heating elements are working. It's possible that one is bad so you're only getting part of your heating ability.
 
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Old 03-05-15, 11:00 AM
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I have a temperature/pressure gauge installed on the top of the unit, tee'd off of where the pressure relief valve sits. I have cranked both thermostats all the way past the hottest setting, as far as they will go and I'm up to 130. I have verified that both thermostats supply voltage to the elements, and that both elements test out at 12 ohms, appropriate for a 4500W element. I can also hear them when I turn it on. It seems everything is working to me. The thermostats aren't labelled in degrees, just hotter colder, so I don't know what their intended max is. I am thinking I need to change them out.

Bud, good call on the low flow shower head. I can hear them complaining already!

When I flush the tank, the water runs clear, but I wonder if there could be sediment build up in there that I'm not seeing. Unit has a combined outlet pipe/anode. Will give that a check, as I've never done anything with it.

Thanks guys,
Jon
 

Last edited by jrlogan1; 03-05-15 at 11:22 AM.
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Old 03-05-15, 12:53 PM
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You have a temperature and pressure gauge T'd in with the temperature and pressure safety valve? I won't even guess if that is permitted or not but if there is no water flow past the temp probe you will not get an accurate reading. You would need your temp sensor in the outlet from the tank, before the mixing valve and check it when hot water is being used. Or, if you have an extra plug in the top of the tank or switch out an anode to get the probe into the tank.

You say you hear "them" when you turn it on. Most heaters only turn on one element at a time but if you actually gotten 240 going to both elements depending on the tanks condition then they are good.

There is probably some sediment in the tank but it has little affect on an electric tanks heating ability unless scale has built up and is coating the heating elements.
 
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Old 03-05-15, 05:40 PM
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While I concede that there is a possibility that the temp gauge isn't perfectly accurate, it is at the highest point in the tank, and of course, the top of the tank is the hottest water. If the water at the temp gauge is cooler than the rest of the tank, it would fall because of increased density and be replaced by lower density hotter water. It might be a few degrees cooler in reading than the actual because of this, but it's pretty close. I have used an infrared thermometer on the outlet line while water was flowing and they agree pretty well.

I have not heard "them" simultaneously turn on, but have confirmed each one by adjusting each thermostat to hear one at a time.

Scale on the elements is a good idea. I might pull them and check. I have well water that is somewhat hard, and scale builds up on lots of things in my system. If they do have scale on them, can you just scrape it off and re-install? Or should I put in new elements? If I use the same elements, is it likely I will get away with using the same O-rings?
 
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Old 03-05-15, 06:20 PM
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Scale on the elements is a good idea. I might pull them and check.
I wouldn't waste my time pulling them, I can tell you they have scale on them. The scale pops off as water is heated and drops to the bottom of the tank. When enough scale builds up on the bottom to reach the lower element, it will insulate the lower element and that element will burn out. At this point you have the choice of cleaning out the tank or replacing the heater.
 
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Old 03-06-15, 06:22 AM
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I'm on a well too and have a electric heater. The scale builds up and falls off on it's own.

As for the temp sensor location. Yes, heat does rise. But your thermometer is not at the highest point of the tank. It's not inside the tank at all. It's in a closed end, passage coming out of the top of your heater where there will be very little water circulation and conduction of heat. The temperature of a tank is not measured that way because of it's extreme inaccuracy.

If you want a more accurate measure pull the lever of your T&P valve and take a sample in a bucket and stick a thermometer in that water. I must warn you though that if your T&P valve has not been tested/opened regularly once you open it it is likely that it will have a slow leak requiring the replacement of the valve. Another method is to simply run the hot water in a fixture until it gets no hotter. Then stick a thermometer in the stream. It will be slightly colder than the water in the heater but it's pretty close.
 
 

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